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2 years ago

Find the square root. ±√1.69 = and

Mathematics

1 answer:

just olya [345]2 years ago

3 0

Answer:

Step-by-step explanation:

√169 = 13

square root and two digits after dot means the result need to has one digit after dot (number of digits after dot divided by 2 because of square root)

so √1.69 = 1.3

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6x - 2 ( x + 4 )= 12

ElenaW [278]

Answer:

x = 5

Step-by-step explanation:

5 0

2 years ago

2. The National Safety Council routinely analyzes the benefit of seat belt use on driver safety. Their data showed that among 28

JulijaS [17]

Answer:

We conclude that there is difference in the proportion of deaths between the 2 groups.

Step-by-step explanation:

We are given that among 2823 drivers not wearing seat belts, 31 died as a result of injuries, and among 7765 drivers wearing seat belts 16 were killed.

Let $p_1$ = proportion of deaths when drivers were not wearing seat belts.

$p_2$ = proportion of deaths when drivers were wearing seat belts.

So, Null Hypothesis, $H_0$ : $p_1=p_2$ {means that there is no difference in the proportion of deaths between the 2 groups}

Alternate Hypothesis, $H_A$ : $p_1\neq p_2$ {means that there is difference in the proportion of deaths between the 2 groups}

The test statistics that would be used here Two-sample z test for proportions;

T.S. = $\frac{(\hat p_1-\hat p_2)-(p_1-p_2)}{\sqrt{\frac{\hat p_1(1-\hat p_1)}{n_1}+\frac{\hat p_2(1-\hat p_2)}{n_2} } }$ ~ N(0,1)

where, $\hat p_1$ = sample proportion of deaths when drivers were not wearing seat belts = $\frac{31}{2823}$ = 0.011

$\hat p_2$ = sample proportion of deaths when drivers were wearing seat belts = $\frac{16}{7765}$ = 0.002

$n_1$ = sample of drivers not wearing seat belts = 2823

$n_2$ = sample of drivers wearing seat belts = 7765

So, the test statistics = $\frac{(0.011-0.002)-(0)}{\sqrt{\frac{0.011(1-0.011)}{2823}+\frac{0.002(1-0.002)}{7765} } }$

= 4.438

The value of z test statistics is 4.438.

Now, at 5% significance level the z table gives critical values of -1.96 and 1.96 for two-tailed test.

Since our test statistic doesn't lie within the range of critical values of z, so we have sufficient evidence to reject our null hypothesis as it will fall in the rejection region due to which we reject our null hypothesis.

Therefore, we conclude that there is difference in the proportion of deaths between the 2 groups.

Also, Margin of error (E) = $1.96 \times \sqrt{\frac{\hat p_1(1-\hat p_1)}{n_1}+\frac{\hat p_2(1-\hat p_2)}{n_2} }$

= $1.96 \times \sqrt{\frac{0.011(1-0.011)}{2823}+\frac{0.002(1-0.002)}{7765} }$

= 0.00397

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3 years ago

If you spend 2.5 hours a week studying for English and 6.5 hours studying for math what is the ratio of time spent studying in m

melisa1 [442]

Answer:

6.5:2.5 or 6.5/2.5 or 6.5 to 2.5

Step-by-step explanation:

A ratio is two numbers put together by a colon, slash (fraction), or "to"

This particular questions asks for math to English, so put in the Math ratio first then English.

8 0

2 years ago

In Lisa’s class 24 of the students are tall and 12 are short in Paul’s class 15 students are tall and 20 students are short whic

artcher [175]

Answer:

Lisa’s

Step-by-step explanation:

Ratio- Tall:Short

Lisa’s Class- 24:12

Paul’s Class- 15:20

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3 years ago

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elena-s [515]

it’s the last one because it’s an open circle so it doesn’t have a line under it and the way the arrow goes has to fit in with the less and greater than sign

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2 years ago

Find the square root. ±√1.69 = ____ and ____

Find the square root. ±√1.69 = and